Bending machine



June 7, 1955 J, L, BOYD 2,710,040

BENDING MACHINE v Filed Oct. 29, 1953 4 Sheets-Sheet l IN VEN TOR.

Joseph L. Boyd ATTORNEY June 7, 1955 J BOYD 2,710,040

BENDING MACHINE Filed Oct. 29, 1955 4 Sheets-Sheet 2 IN V EN TOR.

Joseph L. Boyd ATTORNEY Jul 1e 7, 1955 BOYD 2,710,040

BENDING MACHINE Filed Oct. 29, 195:5 4 SheetLs-Sheet 3 IN V EN TOR.

Joseph L. Boyd ATTORNE Y .1. L. BOYD BENDING MACHINE June 7, 1955 4 Sheets-Sheet 4 Filed 001;. 29, 1953 INVENTOR. Joseph L. Boyd ATTORNEY BENDING MACHINE Joseph L. Boyd, Houston, Tex.

Application October 29, 1953, Serial No. 389,070 8 Claims. cl. 153-20 This invention pertains to bending machines and more particularly to such machines used for bending rods to form the webs of fabricated beams.

It is an object of the invention to provide a simple inexpensive machine for simultaneously making a plurality of bends in a rod.

A further object of the invention is to provide a bending machine that will require a minimum force or pressure to be employed for each bend.

Another object of the invention is to provide such a machine that requires no more force or pressure to be employed than is required to produce a single bend.

Still another object of the invention is to provide a bending machine that will not cause any elongation of the rod between bends. 1

Yet another object of the invention is to provide a bending machine which will produce uniform controlled bends.

Other objects and advantages of the invention will appear from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawings wherein:

Figure 1 is a side elevation of a portion of a bending machine embodying the invention; I

Figure 2 is a plan view of the machine shown in Figure 1;

Figure 3 is a section taken on the line 3-3 of Figure 2;

Figure 4 is a plan view to an enlarged scale of the ends of a pair of adjacent supporting arms;

Figure 4a is a view similar to Figure 4 except that the parts are in the position corresponding to completion of the bending operation.

Figure 4b is a view similar to Figure 4 except on a much larger scale and showing only a portion of the apparatus shown in Figure 4.

Figure 5 is a schematic diagram showing the arrangement of the conduits for supplying pressure fluid to the machine.

Referring first to Figure 1, the machine is supported on a plurality of legs such as shown at 10, 11. These legs carry a pair of parallel pipes 12 and 13. (See also Figure 2.)

Slidably disposed on top of the pipes are a plurality of cylindrical bearings 14 and 15. (See also Figure 3.) Adjacent pairs of bearings on the respective pipes are connected by plates 16.

The machine includes a plurality of sets of arms, each set including a supporting arm 31 or 32 and a cross arm 34 or 35, the sets 31-34 and 3235 differing only as the left hand from the right. The arms of each set are pivotally connected together intermediate the ends thereof and are pivotally connected to one of the plates 16 by means of a pin 19, best seen in Figure 3. The head of the pin is secured in a recess in the supporting arm 31 or 32 and the body of the pin passes through holes in the respective cross arm 34 or 35, and through a washer 22 and a hole in the support 16. The end of the pin nited States Patent 0 "ice is threaded and a nut 23 is screwed thereon to hold the parts together.

Each pair of adjacent sets of arms is connected together. This connection includes in each case a first link (see Figures 2 and 4), which is pivotally connected at its ends to the ends of the adjacent supporting arms 31 and 32, and a second link 33 pivotally connected at its ends to the ends of the adjacent cross arms 34, 35.

Means are provided between each of the links 30, 33 to push them apart and draw them together as desired. This means comprises in each case a cylinder (Figure 2) secured to the links 33, 41, a piston 42 reciprocable within the cylinder 40, and a piston rod 43 connected at one end to the piston and passing through a suitable packing gland or seal in one end of the cylinder and connected at its other end to link 30.

Beneath each of the piston rods is disposed a tie rod 45. It is connected at one end to the link 33 and at the other end passes through a hole in link 30. On the end of rod 45 are screwed a pair of nuts 43, 47, which provide an adjustable stop which limits the separation of links 33 and 30. As will apear, the degree of separation of links 33 and 30 determines the angle of bend of the rod being bent.

Means is provided at the end of each of the supporting arms adjacent the link 30 for receiving a rod, such as placed thereon to be bent, and holding the rod against lateral motion relative to the supporting arm during the bending operation. This means comprises in each case a pair of blocks 51, 52, on arm 31 and blocks 53, 54 on arm 32 (see Figures 2 and 4). During the bending operation these blocks support the sides of the rod 50 so that a pure bending moment is applied to the part of the rod therebetween and no tension or compression is applied to the rods between the bends.

In order to support the inner radius of the bend during the bending operation, the adjacent ends of the blocks 52, 53 are curved as shown at 55 and 56 to provide cylindrical surfaced abutments which push the rod laterally outwardly from the axis of the machine so that there is no flat formed at the point of bend. It will be noted that the axes of curvature of the surfaces of abutments 55, 56 are initially spaced apart in the direction of the axis of the machine and that these axes approach each other during the bending operation as shown in Figure 2. The inner faces 57, 58 of these abutments are relieved, as are also the adjacent surfaces of the arms 31, 32, so that there will be no interference with the pivotal motion of the arms during the bending operation. When the machine is in position corresponding with maximum bend of the rod the axes of curvature of the surfaces of abutments 55, 56 will substantially coincide.

Referring to Figure 5 each of the power cylinders is provided with a connection at one end such as shown at 60, which in turn is connected to a manifold 61 and a connection at the other end such as shown at 62, which in turn is connected to manifold 63. Manifolds 61 and 63 are connected to two ports of a four way valve 64. The other two ports of valve 64 are connected to a line 65 supplying pressure fluid and to a pipe 66 exhausting to atmosphere. Depending on the position of the valve either one of manifolds 61 and 63 may be connected to the source of pressure fluid while the other is connected to the atmospheric exhaust line. By shifting the position of valve 64 pressure fluid may be applied to either end of each of the power cylinders. A three way valve 67 in pipe 65 makes it possible to connect pipe 65 either to pipe 68 connected to the source of pressure fluid (not shown) or to pipe 69 to atmosphere.

To use the machine valve 64 is turned to connect the inner ends of the power cylinders to the pressure fluid so that the supporting arms are all aligned. This is the position illustrated fragmentarily in Figure 4. The rod to be bent is then placed on top of the supporting arms between the lateral supporting blocks 5254. Valve 64 is then turned so as to apply pressure fluid to the outer ends of the power cylinders, which causes the links 30, 33 to separate, which in turn causes the supporting arms to turn at angles to each other, thereby bending the rod around the curved abutments such as 55, 56. When the machine has reached the end of its stroke, the valve 67 can be turned to exhaust position to relieve the pressure, and the rod 50 may then easily be lifted from the supporting arms, this being by virtue of the fact that the rod tends to spring back and straighten out slightly after it has been bent, so as to free itself from the arms.

If it is desired to produce rods for the webs of fishbelly joists in which the lengths of the straight portions of the rod between bends are progressively shorter from the center toward the ends of the rod, it is only necessary to provide the machine with shorter supporting arms near the ends and adjust the stroke of the power cylinders accordingly. In general, by varying the lengths of the arms any desired variation of web width can be produced.

Referring now to Figure 4 and 4a the location of axes 70, 71 of the pivotal connections between the links 30 and the supporting arms 31, 32, is determined as follows:

1. Place 74 and 75 each at a distance R-j-r from center line of machine when in position to receive unbent rod. R is radius of bend and r is radius of rod.

2. Space 74 and 75 apart from each other a distance equal to length of neutral axis of bent portion of rod. If neutral axis is assumed to be the central axis, then this distance is ISO-A 360 where A is internal angle between portions of rod on opposite sides of a bend.

3. Draw arcs with 74 and 75 as centers and tangent to near edges of rod holders.

4. Locate end points M, N of arcs distances Centers 70, 71 can be located anywhere on lines OX I and OY. If located farther from 0 than F and G, the sides 57, 58 must be bevelled off at their ends, as shown, to prevent interference. Centers 70, 71 are preferably located, as shown, at the intersection of the lines OX and OY with perpendiculars to line 74-75 erected from points 74, 75. This tends to prevent stresses on the rod between the bends. With A equal to 60 degrees this locates points 70, 71 close to the far edge of the rod from 74, 75. It is desirable that 70, 71 be on the opposite side of the rods central axis from 74, 75 in order that the axes formed by pins 19 will always move together during the bending operation, so that the machine operates smoothly, as contrasted with the uneven operation which would occur if the pivot axes 70, 71 were on the same side of the rod axes as cylinder axes 74, 75, in which case the initial motion of pivot pins 19 would be one of separation, followed by a motion together after links 30 passed dead center.

The action of the cylindrical surfaced abutments 55,

56, in shaping the bend is to be contrasted with the action taking place when a rod is bent around a single cylindrical pin or die. According to the invention, in which it may be said that a split pin or die is used, the contact between the rod and the split pin is initially only at the outer ends of the bend and progresses in toward the center of the bend as the bend it made. In bending around a solid pin the initial contact is at the center of the bend.

It will be noted that since there is one power cylinder per bend in the machine the total force or pressure required is no greater than that required to produce a single bend. Furthermore, since a pure bending moment is applied in each bend, there being no tension or compression of the rods between the bends, no force is needed beyond that required for the bending alone' By applying the bending force perpendicular to the rod axis, a minimum force or pressure is needed for each bend. The efliciency of the machine is thus so high that it can be operated with available air pressures instead of requiring the use of hydraulic pressure.

While a preferred embodiment of the invention has been shown and described, it is apparent that many changes and modifications thereof could be made by one skilled in the art without departing from the spirit of the invention, and it is desired to protect by Letters Patent all forms of the invention falling within the scope of the following claims.

I claim:

1. A bending machine comprising a plurality of sets of arms disposed serially alongside of each other in a line forming the axis of the machine, each set comprising a supporting arm and a cross arm, means pivotally connecting together the arms of each set intermediate their ends, means connecting together each pair of adjacent sets of arms, each of the last said means including a first link, axially spaced apart means pivotally connecting said first link to each supporting arm at a point removed from the above described intermediate connection, a second link, and axially spaced apart means pivotally connecting said second link to each cross arm at a point removed from said intermediate connection, support means on each supporting arm adjacent said first link to prevent lateral motion relative to the supporting arm of a member or members placed thereon to be bent, and means connected between each adjacent pair of first and second said links to move said links away from each other to cause said member to be bent at a part thereof in between the pairs of said support means adjacent each of said first links.

2. A bending machine comprising a plurality of sets of arms disposed serially alongside of each other in a line forming the axis of the machine, each set comprising a supporting armand a cross arm, means pivotally connecting together the arms of each set intermediate their ends, means connecting together each pair of adjacent sets of arms, each of the last said means including a first link, axially spaced apart means pivotally connecting said first link to each supporting arm at a point removed from the above described intermediate connection, a second link, and axially spaced apart means pivotally connecting said second link to each cross arm at a point removed from said intermediate connection, support means on each supporting arm adjacent said first T link to prevent lateral motion relative to the supporting arm of a member or members placed thereon to be bent, means connected between each adjacent pair of first and second said links to move said links away from each other to cause said member to be bent at a part thereofin-between the pairs of said support means adjacent each of said first links, and second support means on each supporting arm farther from said intermediate connection than the first said support means to cause a predetermined outward lateral motion of said member relative to the axis of the machine during the bending operation to provide the desired shape of curve of said part of the member that is bent.

3. A bending machine comprising a plurality of sets of arms disposed serially alongside of each other in a line forming the axis of the machine, each set comprising a supporting arm and a cross arm, means pivotally connecting together the arms of each set intermediate their ends, means connecting together each pair of adjacent sets of arms, each of the last said means including a first link, axially spaced apart means pivotally connecting said first link to each supporting arm at a point removed from the above described intermediate connection, a second link, and axially spaced apart means pivotally connecting said second link to each cross arm at a point removed from said intermediate connection, support means on each supporting arm adjacent said first link to prevent lateral motion relative to the supporting arm of a member or members placed thereon to be bent, means connected between each adjacent pair of first and second said links to move said links away from each other to cause said member to be bent at a part thereof in between the pairs of said support means adjacent each of said first links, a support extending axially the length of the machine, and means pivotally connected to each pair of arms at said intermediate connection and slidably mounted on said support to support said pairs of arms while permitting said intermediate connections thereof to move closer together during the bending operation.

4. A bending machine comprising a plurality of sets of arms disposed serially alongside of each other in a line forming the axis of the machine, each set comprising a supporting arm and a cross arm, means pivotally connecting together the arms of each set intermediate their ends, means connecting together each pair of adjacent sets of arms, each of the last said means including a first link, axially spaced apart means pivotally connecting said first link to each supporting arm at a point removed from the above described intermediate connection, a second link, and axially spaced apart means pivotally connecting said second link to each cross arm at a point removed from said intermediate connection, support means on each supporting arm adjacent said first link to prevent lateral motion relative to the supporting arm of a member placed thereon to be bent, and means connected between each adjacent pair of first and second said links to move said links away from each other to cause said member to be bent at a part thereof in-between the pairs of said support means adjacent each of said first links, the last said means comprising a cylinder connected at one end to one of said links, a piston in said cylinder, and a piston rod connected at one end to said piston and at the other end to the other of said links.

5. A bending machine comprising a plurality of arms disposed serially along the axis of the machine, a link disposed between each adjacent pair of said arms, axially spaced apart means pivotally connecting each link to each adjacent arm, support means on each arm adjacent each link to prevent lateral motion relative to the arm of a member placed thereon to be bent, and means connected to each pair of adjacent arms and the link there-between to decrease the angle between the arms of the pair to cause said member to be bent at a part thereof in-between the pairs of said support means adjacent the link.

6. A bending machine comprising a plurality of arms disposed serially along the axis of the machine, a link disposed between each adjacent pair of said arms, axially spaced apart means pivotally connecting each link to each adjacent arm, support means on each arm adjacent each link to prevent lateral motion relative to the arm of a member placed thereon to be bent, means connected to each pair of adjacent arms and the link therebetween to decrease the angle between the arms of the pair to cause said member to be bent at a part thereof in-between the pairs of said support means adjacent the link, and second support means on each supporting arm nearer the centers of said links than the first said support means to cause a predetermined outward lateral motion of said member relative to the axis of the machine during the bending operation to provide the desired shape of curve of said part of the member that is bent.

7. A bending machine comprising a plurality of arms disposed serially along the axis of the machine, a link disposed between each adjacent pair of said arms, axially spaced apart means pivotally connecting each link to each adjacent arm, support means on each arm adjacent each link to prevent lateral motion relative to the arm of a member placed thereon to be bent, means connected to each pair of adjacent arms and the link therebetween to decrease the angle between the arms of the pair to cause said member to be bent at a part thereof in between the pairs of said support means adjacent the link, and second support means on each supporting arm nearer said links than the first said support means to cause a predetermined outward lateral motion of said member relative to the axis of the machine during the bending operation to provide the desired shape of curve of said part of the memher that is bent, each of the second support means comprising an abutment having a surface of cylindrical curvature, the axes of curvature of each pair of adjacent abutments of adjacent arms being spaced apart along the axis of the machine and approaching each other as said arms are moved to bend said member.

8. The combination of claim 7 in which the pivot axes of the connections of the first links with the supporting arms are on the opposite side of the axis of the member to be bent from the axes of said abutments.

References Cited in the file of this patent UNITED STATES PATENTS 620,227 Condon Feb. 28, 1899 910,282 Gerlock Ian. 19, 1909 975,184 Walsh Nov. 8, 1910 1,867,581 Marietta July 19, 1932 2,086,736 Palmer July 13, 1937 2,203,027 Onsrud June 4, 1940 2,316,049 Connor Apr. 6, 1943 2,491,893 Duer Dec. 20, 1949 2,661,787 Eidal Dec. 8, 1953 FOREIGN PATENTS 31,121 France Apr. 5, 1927 617,362 Australia May 18, 1934 867,035 France June 30, 1941 

